The present invention relates to a new and improved method of, and apparatus for, forming an imbricated formation from printed products, such as newspapers, periodicals, magazines or the like and which arrive in an imbricated stream.
Generally speaking, the method for forming an imbricated formation from printed products arriving in an imbricated stream, is of the type wherein by increasing or decreasing the conveying velocity and by accordingly altering the pitch or spacing between successive products the infed imbricated formation is transformed into an outfed imbricated formation having a different imbrication, i.e. pitch or spacing between successive products as compared to the infed imbricated formation.
The apparatus for forming a desired imbricated formation having a predetermined pitch of printed products arriving in an imbricated stream, such as newspapers, periodicals, magazines or the like, is of the type comprising a first conveyor or conveying device for the infeed of the imbricated stream of arriving printed products moving in a predetermined direction, and a second conveyor or conveying device arranged downstream of the first conveyor with respect to the predetermined direction of movement of the imbricated stream of printed products. There are provided a control device for controlling a conveying velocity of the second conveyor as well as drive means for driving the second conveyor at the controlled conveying velocity.
From Swiss Patent No. 657,833 and the corresponding Canadian Patent No. 1,225,107 issued Aug. 4, 1987, with which there are cognate the aforementioned related United States patent and patent application, there is known a method and apparatus for forming multi-layer coils or packages from printed products arriving in an imbricated formation or stream. This known apparatus comprises two successively arranged conveyors or conveyor devices, wherein the conveying velocity of the downstream conveyor can be altered in relation to the conveying velocity of the upstream conveyor in order to adjust to a predetermined value the thickness of the imbricated formation which is delivered to the wound package. By means of a tachogenerator, there is measured the conveying velocity of the upstream conveyor and such is delivered to an adjustable control device by means of which the conveying velocity of the downstream conveyor is appropriately adjusted or controlled. After such adjustment, the control device ensures that the relationship or ratio between the conveying velocities of both successively arranged conveyors remains essentially constant. In other words, the pitch in the outfed imbricated formation is increased or decreased relative to the pitch of the infed imbricated formation by an amount ensuring that the outfed imbricated formation has essentially constant thickness. As long as the printed products within the arriving or infed imbricated formation or stream are arranged at a constant successive spacing or pitch there is possible the formation of an outfed imbricated product formation or stream of essentially constant thickness, whereas if there prevails an irregular or non-uniform spacing or pitch between the printed products in the arriving or infed imbricated formation, this irregularity is maintained and not compensated in the outfed imbricated formation.
Furthermore, there is known from the European Published Patent No. 0,054,735, published June 30, 1982, an apparatus for forming wound coils or coiled packages from sacks or workpieces which arrive in imbricated formation. With this apparatus the sacks are delivered by means of two successively arranged conveyors to the package. At the drive shaft of the second conveyor, there is arranged a pulse transmitter which outputs pulses corresponding to the angle of rotation of the drive shaft and delivers such to a counter. The counter adds the number of pulses and is repeatedly reset to null whenever a scanning device at the region of the first conveyor detects a further sack which has been delivered in the infed imbricated formation on the first conveyor. If the counter is not reset before it has reached a predetermined threshold value, then the drive motor of the second conveyor is turned off and only restarted as soon as the scanning device has again detected a sack delivered by means of the first conveyor
This apparatus does not have any means to deliberately alter the pitch of the imbricated formation. In fact, the apparatus can only make a correction, if the pitch between two successive products accidentally or occasionally becomes greater than the predetermined pitch value which is set by the predetermined threshold value at the counter of the sack-making machine. Instead of turning off and restarting, the motor can also be run at different speeds in order to correct for irregularities in the pitch of the infed imbricated formation. However, the apparatus is not intended or structured to produce an outfed imbricated formation having a pitch which is different from the pitch of the infed imbricated formation.